As a coil winding machine for winding a wire around the core of a rotor of a rotating electrical machine, a flyer type coil winding machine of a type provided with a flyer is known from, for example, Japanese Unexamined Patent Publication No. 2008-278587 etc. This flyer type coil winding machine makes a flyer rotate around a flyer rotation axis (Y-axis) perpendicular to a rotor axis (X-axis) while feeding out wire from a nozzle provided at the front end of the flyer (this type referred to as a nozzle rotation type). Further, it guides the wire by a guide part to a predetermined plurality of slots of the core of the rotor and winds it along paths including the slots. FIG. 1 shows an example of using a flyer type coil winding machine to wind a coil.
In such a flyer type coil winding machine, if winding a coil between slots of a core 23 facing each other across about 180 degrees, the shape of the coil at the coil end face bulged up in the axial direction like a mound and the desired shape could not be obtained. That is, the height dimension h became larger, the allowable height h0 was exceeded, and the result became no good (see FIG. 1).
That is, if winding the wire separated into layers, the wire is superposed at the center part of the end face of the core 23, so the wire inevitably bulges up in a mound shape. When the coil is not wound at the predetermined position at each different layer, coil wound at the next layer is not wound at a stable position, so the allowable height h0 ends up being exceeded in some cases. For this reason, the problem arose that it was not possible to satisfy the product specification size and the “occupancy rate” defined by the ratio of the area of the actually wound wire to the area which can be wound by the coil.